Chionoracium (Stenotheca) is a New World subgenus (subgen. Mandonia is nowadays merged together with subgen. Chionoracium by most authors) consisting of diploid sexual plants only. In contrast to Hieracium and Pilosella, Chionoracium is, namely in South America, very poorly explored. It has a mostly montane distribution throughout both North and South America. The only major studies after Zahn's monograph are a taxonomic revision of the subgenus in Central America and a comparative morphological study of achene morphology, anatomy and surface ultrastructure based on a rather small number of species. In contrast to subgen. Hieracium, also autogamy was reported here. The species occupy thermophilous and mesophilous deciduous forests, forest margins, various types of grasslands, open vegetation on mountain top plateaux, rock outcrops and rarely xerophytic shrubs.

About Hieracium

Hieracium subg. Chionoracium